In order to investigate the atomization characteristics of the pressure-swirl nozzle for dust reduction, a multiscale method was proposed. The method distinguishes between internal flow field, primary atomization and secondary atomization. Based on the large eddy simulation (LES) model and the volume of fluid (VOF) model, the adaptive mesh refinement (AMR) method was introduced to predict the breakup of liquid core. Then the random generation method of the droplet with constant radius and the Kelvin-Helmholtz Rayleigh-Taylor (KH-RT) was used to calculate the secondary breakup of the bigger droplets. Besides, the radial and axial distribution laws of velocity, mean diameter and concentration of droplets was obtained under the spray pressure of 1-6 MPa. According to the crushing and collision-polymerization efficiency, the droplet field was divided into three phases. Based on phase-doppler anemometry (PDA), the relative error of the mean droplet diameter between simulation and experiments was less than 21.4%. (C) 2020 Elsevier B.V. All rights reserved.